Rapid formation of Cu/Cu3Sn/Cu joints using ultrasonic bonding process at ambient temperature

摘要

Wafer bonding using Sn interlayer and silicon bond components with Ti/Ni/Cu metallization was achieved by ultrasonic bonding at ambient temperature for 4?s under 0.6?MPa. High-melting-point joint which fully consisted of Cu3Sn intermetallic compounds was formed with a high shear strength of 65.8?MPa and a low electrical resistivity of 67.3?μΩ?·?cm. Experimental results showed that ultrasonic vibration induced steep temperature rise at rubbing interface, melting solid solder, and sequent ultrasonic effects at the liquid Sn/solid Cu interface dominated the mechanism and kinetics of rapid formation of Cu3Sn joint.